Angled tissue cutting instrument having variably positionable cutting window and indexing tool for use therewith

ABSTRACT

An angled tissue cutting instrument includes an outer member having an elongate body with a bend and a forward end, and a distal tip rotatably mounted on the forward end. The distal tip and body are rotatable relative to one another about a central longitudinal axis of the tip to variably position a cutting window of the tip in a selected directional position about the axis. Relative rotation between the distal tip and the body about the axis is prevented to lock the cutting window in a selected directional position when the outer member is maintained in a longitudinally extended position by an inner member of the instrument disposed within the outer member. An indexing tool for the angled tissue cutting instrument has a socket for receiving the distal tip to effect rotational indexing. A method of variably positioning a cutting window of an angled tissue cutting instrument involves rotationally indexing a distal tip of an outer member of the instrument and maintaining the distal tip in a selected rotationally indexed position.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a divisional of prior U.S. patent application Ser.No. 10/760,352 filed Jan. 21, 2004 now U.S. Pat. No. 7,276,074, theentire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to angled tissue cuttinginstruments including an elongate outer member having a bend and adistal end with a cutting window and, more particularly, to angledtissue cutting instruments in which the cutting window is variablypositionable relative to the bend, to indexing tools for variablypositioning the cutting windows of angled tissue cutting instruments,and to methods of variably positioning a cutting window of an angledtissue cutting instrument.

2. Brief Discussion of the Related Art

Tissue cutting instruments comprising an elongate outer tubular memberand an elongate inner member rotatably disposed in the outer tubularmember to cut anatomical tissue have become well-accepted for use invarious surgical procedures. Typically, the inner member has a distalend with a cutting edge and the outer member has a distal end with acutting window through which the cutting edge is exposed to cutanatomical tissue when the inner member is rotated within the outermember. The cutting edge may have various configurations in accordancewith the type of tissue and/or the type of cutting action to beaccomplished. In some instances, the distal end of the outer member hasa cutting edge cooperable with the cutting edge of the inner member tocut the anatomical tissue as the inner member is rotated. The outer andinner members ordinarily have proximal ends adapted for coupling with apowered surgical handpiece used to rotate the inner member relative toand within the outer member. Many tissue cutting instruments provide foraspiration of anatomical debris through the tissue cutting instrumentand/or irrigation at the operative or cutting site via an irrigating orflushing fluid supplied along the tissue cutting instrument.

In tissue cutting instruments of the foregoing type, the outer membersmay be longitudinally or axially straight or may be longitudinally oraxially bent, angled or curved. Depending on the location of the cuttingsite in the patient's body, angled tissue cutting instruments may betterfacilitate positioning of the outer member distal end at the cuttingsite while the handpiece remains external to the patient's body so as toprovide better access to the cutting site from externally of thepatient's body. The bent, angled or curved outer members of angledtissue cutting instruments typically include a proximal length portionextending distally to a bend, angle or curve and a distal length portionextending distally from the bend, angle or curve to the distal end.Where the outer member is longitudinally or axially bent, angled orcurved, the inner member is normally provided with a flexible regionadjacent the bend, angle or curve in the outer member whereby the innermember conforms to the longitudinally or axially bent, angled or curvedconfiguration of the outer member while still being rotatable within theouter member. Angled tissue cutting instruments of the latter type arerepresented by U.S. Pat. No. 177,490 to Fones, U.S. Pat. No. 4,445,509to Auth, U.S. Pat. No. 4,466,429 to Loscher, U.S. Pat. No. 4,646,738 toTrott, U.S. Pat. No. 5,152,744 and U.S. Pat. No. 5,322,505 to Krause etal, U.S. Pat. Nos. 5,286,253, 5,411,514 and U.S. Pat. No. 5,601,586 toFucci et al, U.S. Pat. No. 5,437,630 to Daniel et al, U.S. Pat. No.5,529,580 to Kusumoki et al, U.S. Pat. No. 5,620,415 to Lucy et al, U.S.Pat. No. 5,620,447 to Smith et al, and U.S. Pat. No. 5,922,003 to Anctilet al.

In most angled tissue cutting instruments, the bend, curve or angle isformed in an elongate body of the outer member as part of themanufacturing or fabrication process and is essentially rigid or fixed.The distal end of the outer member is also ordinarily fixed to theelongate body such that the position of the cutting window relative tothe bend, curve or angle is fixed and cannot be varied or adjusted.Accordingly, the outer members of angled tissue cutting instruments arenormally provided with a cutting window in a fixed rotational positionabout a central longitudinal axis of the distal end such that thecutting window faces in a fixed, predetermined direction relative to thebend. This situation presents disadvantages where access to an operativeor cutting site is best established with the bend extending in aparticular direction or orientation but the fixed position of thecutting window relative to the bend in the particular direction ororientation does not face the anatomical tissue intended to be cut withthe instrument at the operative site. While it is possible to rotate theentire instrument to enable the cutting window to face the anatomicaltissue intended to be cut, the direction or orientation of the bend isnecessarily changed thereby and no longer extends in the particulardirection or orientation needed to best establish access to theoperative site. Use of the instrument with the cutting window facing theanatomical tissue intended to be cut but with the bend extending in adifferent direction or orientation may be prohibited due to the presenceof anatomical structure at risk of being traumatized due to contact withthe instrument. Also, rotation of the entire instrument results in thehandpiece being correspondingly rotated, such that the handpiece may nolonger be oriented for proper grasping and manipulation by the surgeon.

U.S. Pat. No. 5,601,586 and No. 5,411,514 to Fucci et al arerepresentative of variable angle tissue cutting instruments in which alongitudinally straight outer member has a spiral relief cut forming anon-rigid bendable section along which the outer member may be bentaxially by a user, and the inner member is flexible to follow the bentconfiguration of the outer member. By bending the outer member along thebendable section, a cutting window at the distal end of the outer membercan be positioned to face in various directions. Directional positioningof the cutting window cannot be accomplished without bending thebendable section and the distal end cannot be rotationally indexed aboutits central longitudinal axis. The longitudinal profile of the outermember cannot be maintained and still allow variable directionalpositioning of the cutting window.

U.S. Pat. No. 5,620,447 to Smith et al relates to an angled tissuecutting instrument in which the outer member has a bendable sectionformed by a spiral relief cut and is also rotatable about itslongitudinal axis to position a cutting window at a distal end thereofin various selected angular positions. The entire outer member must berotated about its axis in order to vary the angular position of thecutting window. Rotation of the outer member is effected at and withrespect to a base at a proximal end of the outer member, the bendablesection being necessary to transmit this rotational torque tocorrespondingly rotate the distal end. A rigid intermediate memberhaving a fixed bend is required between the inner member and thebendable section of the outer member. The bendable section and theintermediate member add undesired structural and functional complexityand cost to the instrument. The base at the proximal end of the outermember requires specialized structure precluding the use of aconventional hub at the proximal end of the outer member.

In view of the foregoing deficiencies of the prior art, a need existsfor an angled tissue cutting instrument in which the distal end andelongate body of the outer member are rotatable relative to one anotherto permit selective rotational indexing of the distal end about itscentral longitudinal axis to variably position the cutting window of thedistal end. A need further exists for an angled tissue cuttinginstrument providing selective directional or angular positioning of thecutting window relative to a bend, angle or curve in the elongate bodyof the outer member without requiring rotation of the entire outermember and/or rotation of the entire instrument. There is also a needfor an angled tissue cutting instrument that permits selectivedirectional or angular positioning of the cutting window relative to arigid or fixed bend, angle or curve in a one-piece elongate body of theouter member. An additional need prevails for an angled tissue cuttinginstrument in which the outer member is movable between a longitudinallyextended position wherein the distal end and elongate body of the outermember are prevented from rotating relative to one another about acentral longitudinal axis of the distal end and a longitudinallyretracted position wherein the distal end and elongate body arerotatable relative to each other about the central longitudinal axis torotationally index the distal end. A still further need exists for anangled tissue cutting instrument in which distal advancement of theinner member in the outer member a full insertion distance locks thecutting window of the outer member in a selected directional positionwhile retraction or withdrawal of the inner member proximally from itsfull insertion distance unlocks the cutting window for rotationalindexing to another selected directional position. There is also a needfor an indexing tool for rotationally indexing a distal end of an outermember so that the fingers of a person's hand do not contact the distalend and particularly do not contact sharp cutting edges on and/orexposed from the distal end. Moreover, there is a need for a kitsupplying both an angled tissue cutting instrument having a variablypositionable cutting window and an indexing tool for variablypositioning the cutting window. Another need exists for a method ofvariably positioning a cutting window at a distal end of an outer memberof an angled tissue cutting instrument by rotationally indexing thedistal end by rotating it about its central longitudinal axis relativeto an elongate body of the outer member, as permitted by relativelongitudinal movement between the distal end and elongate body.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to overcome theaforementioned disadvantages of prior angled tissue cutting instruments.

Another object of the present invention is to permit selective relativerotation between a distal end and elongate body of an outer member of anangled tissue cutting instrument about a central longitudinal axis ofthe distal end to adjustably position a cutting window of the distalend.

A further object of the present invention is to effect relative rotationbetween a distal end and elongate body of an outer member of an angledtissue cutting instrument about a central longitudinal axis of thedistal end to position a cutting window of the distal end at variousrotational positions about the central longitudinal axis.

It is also an object of the present invention to selectively adjust thedirectional or angular orientation of a cutting window in a distal endof an outer member of an angled tissue cutting instrument relative to abend in an elongate body of the outer member rotatably mounting thedistal end.

The present invention also has as an object to prevent relative rotationbetween a distal end and elongate body of an outer member of an angledtissue cutting instrument when the outer member is in a longitudinallyextended position and to permit relative rotation between the distal endand elongate body when the outer member is in a longitudinally retractedposition to variably position a cutting window of the distal end.

Moreover, it is an object of the present invention to utilize relativelongitudinal movement between a distal end and elongate body of an outermember of an angled tissue cutting instrument to selectively prevent andselectively permit rotational indexing of the distal end.

The present invention has as an additional object to prevent relativerotation between a distal end and elongate body of an outer member of anangled tissue cutting instrument about a central longitudinal axis ofthe distal end when an inner member of the instrument is disposed withinthe outer member a full insertion distance and to permit relativerotation between the distal end and elongate body about the centrallongitudinal axis when the inner member is retracted from its fullinsertion distance.

It is also an object of the present invention to lock the outer memberof an angled tissue cutting instrument in a longitudinally extendedposition preventing relative rotation between a distal end and elongatebody of the outer member in response to an inner member of theinstrument being disposed within the outer member a full insertiondistance and to release the outer member for movement to alongitudinally retracted position permitting relative rotation betweenthe distal end and elongate body in response to the inner member beingretracted from the full insertion distance.

An additional object of the present invention is to allow a singleangled tissue cutting instrument to access an operative site with a bendof an outer member of the instrument extending in a particular directionand to cut anatomical tissue at different directional locations at theoperative site via a cutting window in a distal end of the outer memberwithout changing the particular direction for the bend.

Yet another object of the present invention is to accomplish rotationalindexing of a distal end of an outer member of an angled tissue cuttinginstrument about a central longitudinal axis of the distal end withoutrotating the entire outer member or the entire instrument.

The present invention has as a further object to provide an indexingtool by which a distal end of an outer member of an angled tissuecutting instrument can be moved proximally and rotated relative to anelongate body of the outer member without a person's hand contacting thedistal end.

The present invention also has as an object to provide an indexing toolfor mechanically applying the forces needed to move an outer member ofan angled tissue cutting instrument from a longitudinally extendedposition to a longitudinally retracted position and to rotationallyindex a distal end of the outer member.

Another object of the present invention is to make available a kitcomprising an angled tissue cutting instrument and an indexing tool forrotationally indexing a distal end of the outer member of the angledtissue cutting instrument to adjust the position of a cutting window inthe distal end.

The aforesaid objects are achieved individually and in combination, andit is not intended that the present invention be construed as requiringtwo or more of the objects to be combined unless expressly required bythe claims attached hereto.

Some of the advantages of the present invention are that directionalpositioning of the cutting window is accomplished without requiring aflexible bendable section in the elongate body of the outer member; theelongate body can be fabricated as one-piece with a rigid bend; theelongate body of the outer member may include a plurality of bendsextending in the same or different directions and at the same ordifferent angles; the same instrument can be used to cut anatomicaltissue located medially, laterally, superiorly and inferiorly to thedistal end of the outer member positioned at an operative site with abend of the outer member extending in a particular direction to accessthe operative site; standard hubs can be used to mount the proximal endsof the outer and inner members; the angled tissue cutting instrumentdoes not require an intermediate member between the inner and outermembers; the distal end may be locked in various rotationally indexedpositions; various types of engagement structure can be provided in theangled tissue cutting instrument for preventing relative rotationbetween the distal end and elongate body in the longitudinally extendedposition for the outer member; the distal end may be a one-piece memberor may be formed of multiple parts; selective directional positioning ofthe cutting window can be accomplished quickly and reliably duringsurgery; the risk of a surgical glove being unintentionally torn by acutting edge of the instrument is avoided since the indexing tool avoidscontact of the gloved hand with the outer member distal end; properplacement of the indexing tool on the distal end of the outer member isensured; the indexing tool is easy to use; various inner membersconventionally used in angled tissue cutting instruments may be used asthe inner member of the angled tissue cutting instrument of the presentinvention; the inner member can be retracted from the full insertiondistance while remaining within the outer member such that the innermember does not have to be fully withdrawn from the outer member topermit rotational indexing of the outer member distal end; the innermember remaining within the outer member in the longitudinally retractedposition for the outer member controllably limits retraction of thedistal end within the elongate body in the longitudinally retractedposition; extension of the distal end from the elongate body in thelongitudinally extended position is also controlled to preventdetachment of the distal end from the elongate body; depending on howthe inner and outer members are coupled to the handpiece, retraction ofthe inner member from its full insertion distance may be accomplishedwhile the inner and outer members are detached from the handpiece orwhile the inner and outer members remain attached to the handpiece; theangled tissue cutting instrument may be provided with or without anaspiration passage; the angled tissue cutting instrument may be providedwith or without an irrigation passage; and leakage of irrigation fluidmay be prevented via a seal between the distal end and elongate body.

These and other objects, advantages and benefits are realized with thepresent invention as generally characterized in an angled tissue cuttinginstrument comprising an outer member and an inner member movablydisposed in the outer member. The outer member includes a distal end ortip rotatably mounted to a forward end of an elongate body having abend. The distal tip has a central longitudinal axis and a cuttingwindow from which a cutting tip of the inner member is exposed to cutanatomical tissue when the inner member is moved within the outermember. The distal tip and body are selectively rotatable relative toone another about the central longitudinal axis to variably position thecutting window in a selected one of a plurality of directional positionsabout the central longitudinal axis. Relative rotation between thedistal tip and the elongate body about the central longitudinal axis isprevented to lock the cutting window in a selected directional positionwhen the outer member is in a longitudinally extended position. Relativerotation between the distal tip and the elongate body about the centrallongitudinal axis is permitted when the outer member is in alongitudinally retracted position to permit rotational indexing of thedistal tip to position the cutting window in another selected one of thedirectional positions.

Engagement structure is provided in the instrument to prevent relativerotation between the distal tip and the body when the outer member is inthe longitudinally extended position. In one embodiment, the engagementstructure comprises body engagement structure including a plurality ofbody protrusions and body slots on the elongate body cooperativelyinterengageable with tip engagement structure including a plurality oftip slots and tip protrusions, respectively, on the distal tip.Cooperative interengagement between the body engagement structure andthe tip engagement structure prevents relative rotation between thedistal tip and the elongate body about the central longitudinal axis.The body engagement structure is cooperatively interengaged with the tipengagement structure when the outer member is in the longitudinallyextended position and is disengaged from the tip engagement structurewhen the outer member is in the longitudinally retracted position.

The longitudinally extended and longitudinally retracted positions areobtained via relative longitudinal movement between the distal tip andthe elongate body. In the longitudinally extended position, the distaltip is extended longitudinally distally from the forward end of theelongate body and, in the longitudinally retracted position, the distaltip is retracted longitudinally proximally relative to the elongatebody. The outer member may be placed in the longitudinally extendedposition in response to distal advancement of the inner member withinthe outer member to a full insertion distance, causing distal extensionof the distal tip from the elongate body. The outer member may bemaintained or locked in the longitudinally extended position by theouter member and the inner member being releasably attached to ahandpiece. The inner member may be withdrawn or moved proximallyrelative to the elongate body of the outer member a sufficient distancefrom its full insertion distance so that relative longitudinal movementis permitted between the distal tip and the elongate body by which theouter member may be placed in the longitudinally retracted position. Thecutting window is maintained in a selected directional position bymoving the outer member from the longitudinally retracted position tothe longitudinally extended position. Movement of the outer member fromthe longitudinally retracted position to the longitudinally extendedposition may be accomplished in response to distal advancement of theinner member the full insertion distance within the outer member,thereby causing the body engagement structure to cooperativelyinterengage with the tip engagement structure with the cutting window inthe selected directional position. Where the outer and inner membershave been detached from the handpiece, reattachment of the outer andinner members to the handpiece secures the outer member in thelongitudinally extended position in which the engagement structureprevents relative rotation between the distal tip and the elongate bodyabout the central longitudinal axis.

The present invention is also generally characterized in an indexingtool for use with an angled tissue cutting instrument that has an outermember including an elongate body and a distal tip with a cuttingwindow. The indexing tool comprises a retention element, a handleextending from the retention element, and external indicia. Theretention element has a central longitudinal axis and a socket forremovably receiving the distal tip of the outer member of the angledtissue cutting instrument. The socket has a configuration to mate withan external configuration of the distal tip when the distal tip is in aninsertion orientation relative to the socket. The external indicia ofthe indexing tool is alignable with the cutting window of the distal tipto obtain the insertion orientation. The handle is movable to move theretention element longitudinally along its central longitudinal axis toapply axial force to the distal tip received in its socket by which thedistal tip is retracted proximally relative to the elongate body of theouter member. The handle is movable to move the retention elementrotationally about its central longitudinal axis to apply rotationalforce to the retracted distal tip received in the socket by which thedistal tip is rotated relative to the elongate body to effect rotationalindexing of the cutting window.

The present invention is additionally characterized in an angled tissuecutting instrument kit comprising an angled tissue cutting instrumentand an indexing tool. The angled tissue cutting instrument includes anelongate outer member and an elongate inner member movably disposed inthe outer member. The outer member includes an elongate body having abend and a forward end, and a distal tip mounted on the forward end. Thedistal tip has a central longitudinal axis and a cutting window radialto the central longitudinal axis. The distal tip is movablelongitudinally relative to the elongate body from a longitudinallyextended position to a longitudinally retracted position in response toaxial force on the distal tip. The distal tip is rotatable relative tothe elongate body about its central longitudinal axis in thelongitudinally retracted position to adjust the radial position of thecutting window about the axis in response to rotational force on thedistal tip. The distal tip is prevented from rotating relative to theelongate body in the longitudinally extended position to lock thecutting window in a selected radial position about the axis. Theindexing tool comprises a retention element having a socket forremovably receiving the distal tip and a handle extending from theretention element. The indexing tool is movable via the handle to applythe axial force on the distal tip to move the distal tip from thelongitudinally extended position to the longitudinally retractedposition and to apply the rotational force on the distal tip to rotatethe distal tip relative to the elongate body about the centrallongitudinal axis. The socket preferably has a configuration to matewith an external configuration of the distal tip in an insertionorientation. Preferably, the indexing tool comprises external indicia,and the insertion orientation for the distal tip corresponds toalignment of the cutting window with the indicia.

The present invention is further generally characterized in a method ofvariably positioning the cutting window of an angled tissue cuttinginstrument, comprising the steps of effecting relative rotation betweena distal tip and an elongate body of an outer member of the angledtissue cutting instrument about a central longitudinal axis of thedistal tip with the outer member in a longitudinally retracted positionto move a cutting window of the distal tip to a selected directionalposition about the axis, advancing an inner member of the angled tissuecutting instrument distally within the outer member with the cuttingwindow in the selected directional position to move the outer member toa longitudinally extended position, preventing relative rotation betweenthe distal tip and the elongate body about the central longitudinal axisin response to the step of advancing, and locking the outer member inthe longitudinally extended position such that the cutting window islocked in the selected directional position. Effecting relative rotationbetween the distal tip and the elongate body may be preceded by thesteps of moving the outer member from the longitudinally extendedposition to the longitudinally retracted position and disengaging tipengagement structure on the distal tip from body engagement structure onthe body in response to the step of moving. The step of moving mayinvolve withdrawing the inner member proximally within the outer memberand retracting the distal tip proximally relative to the elongate body.The step of advancing may involve extending the distal tip distally fromthe elongate body. The step of preventing relative rotation may includeengaging the tip engagement structure with the body engagementstructure. The step of locking may include releasably attaching proximalends of the outer and inner members to a handpiece.

Other objects, features and advantages of the present invention willbecome apparent from the following description of the preferredembodiment taken in conjunction with the accompanying drawings, whereinlike parts in each of the several figures are identified by the samereference characters.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an angled tissue cutting instrument accordingto the present invention shown in exploded relation to a handpiece.

FIG. 2 is a broken, exploded side view of the angled tissue cuttinginstrument.

FIG. 3 is a broken, exploded side view of an outer member of the angledtissue cutting instrument.

FIG. 4 is a forward end view of an elongate body of the outer member.

FIG. 5 is an enlarged fragmentary view of the forward end of theelongate body.

FIG. 6 is a top view of a distal tip of the outer member.

FIG. 7 is a sectional view of the distal tip taken along line 7-7 ofFIG. 3.

FIG. 8 is a sectional view of the distal tip taken along line 8-8 ofFIG. 3.

FIG. 9 is a broken longitudinal sectional view of the instrumentdepicting the outer member locked in a longitudinally extended positionpreventing relative rotation between the distal tip and the elongatebody about a central longitudinal axis of the distal tip.

FIG. 10 is a broken longitudinal sectional view of the instrumentdepicting the outer member in a longitudinally retracted positionpermitting relative rotation between the distal tip and the elongatebody about the central longitudinal axis to rotationally index thedistal tip.

FIG. 11 is a broken longitudinal sectional view of the instrumentillustrating the outer member locked in the longitudinally extendedposition subsequent to rotational indexing of the distal tip.

FIG. 12 is a broken perspective view showing the distal tip locked in afirst rotational position about the central longitudinal axis.

FIG. 13 is a broken perspective view illustrating the distal tip lockedin a second rotational position about the central longitudinal axis.

FIG. 14 is a broken perspective view showing the distal tip locked in athird rotational position about the central longitudinal axis.

FIG. 15 is a broken perspective view depicting the distal tip locked ina fourth rotational position about the central longitudinal axis.

FIG. 16 is a top sectional view of an alternative distal tip ofmulti-part construction.

FIG. 17 is an exploded top sectional view of the alternative distal tip.

FIG. 18 is a perspective view of an indexing tool for the angled tissuecutting instrument.

FIG. 19 is a side view of the indexing tool.

FIG. 20 is an end view of the indexing tool.

FIG. 21 is a side sectional view of the indexing tool.

FIG. 22 is a broken perspective view illustrating an angled tissuecutting instrument kit comprising the indexing tool and the angledtissue cutting instrument and depicting use of the indexing tool torotationally index the distal tip of the outer member of the angledtissue cutting instrument.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An angled tissue cutting instrument or blade 10 is illustrated in FIGS.1 and 2 and includes an elongate outer tubular member 12 and an elongateinner member 14 rotatably or movably disposed within the outer member.Outer member 12, which may be considered an outer blade member, includesa distal end or tip 16 and an elongate body 18 having a forward endrotatably mounting distal tip 16. Body 18 has a rearward or proximal endcoupled to an outer member hub 20, a proximal length portion 22extending distally from outer member hub 20 to a bend, curve or angle24, and a distal length portion 26 extending distally from bend 24 tothe forward end at an angle A relative to a central longitudinal axis 28of the proximal length portion. The proximal and distal length portions22 and 26 are each shown as having a longitudinally or axially straightconfiguration with angle A defined between a central longitudinal axis30 of the distal length portion and the central longitudinal axis 28 ofthe proximal length portion. However, it should be appreciated that theproximal and distal length portions can have various non-straightconfigurations including one or more additional bends, curves or angles.The bend 24 is essentially rigid or fixed, with the body 18 beingessentially a rigid, one-piece member formed by bending a continuous andunbroken tubular member of solid wall construction to pre-form the bend24 therein during the fabrication or manufacturing process. The angle A,radius of curvature R and location of the bend 24 may vary depending onthe surgical procedure in which the angled tissue cutting instrument isto be used, and the outer diameter of the body 18 may also vary.Representative but not limiting angles A for the bend 24 include 12°,40°, 45° and 60°. Where the elongate body 18 has more than one bend, thebends may extend in the same direction or in different directions fromone another and may have the same angle or different angles from oneanother.

As best shown in FIG. 3, the proximal end of elongate body 18 may beknurled to facilitate attachment to outer member hub 20. An inlet port32 may be formed in the proximal end of the body 18 for communicationwith an irrigation port of a powered surgical handpiece as explainedfurther below. The body 18 comprises body engagement structureselectively cooperatively interengageable with tip engagement structureof distal tip 16 to prevent relative rotation between the tip and bodyabout axis 30. The body engagement structure is depicted by way ofexample as comprising body protrusions and slots for selectivelycooperatively interengaging tip slots and protrusions, respectively,depicted by way of example as forming the tip engagement structure.However, it should be appreciated that the body engagement structure andthe tip engagement structure can be designed in various ways. As bestshown in FIGS. 3-5, the forward end of body 18 has a plurality ofarcuately or circumferentially extending edge segments 34 in a planeperpendicular to axis 30 and a plurality of arcuately orcircumferentially extending body protrusions or keys 36 extendingdistally or forwardly from the edge segments 34 at an angle in thedirection of axis 30. The body protrusions 36 are spaced from oneanother at radial locations about the axis 30, and the edge segments 34are disposed between the body protrusions to define an arcuately orcircumferentially extending body slot or keyway 37 between each pair ofradially adjacent body protrusions. Although the number of edge segments34 and body protrusions 36 may vary, body 18 is illustrated by way ofexample as having four body protrusions 36 at 90° spaced radiallocations about the axis 30 and four edge segments 34 alternatinglyarranged with the body protrusions about the axis 30 such that the bodyslots 37 are also spaced 90° from one another.

The forward end of body 18 has an opening in the plane of edge segments34 communicating and coaxial with the lumen 38 through body 18. The body18 is of uniform outer diameter and uniform inner diameter between theproximal end and edge segments 34, and the lumen 38 is of uniformdiameter. The body protrusions 36 extend angularly inwardly from theedge segments 34 in the forward or distal direction to terminate atarcuately or circumferentially extending forward edges, and the forwardedges of the body protrusions 36 circumscribe an opening coaxial withlumen 38. The inner surfaces of the body protrusions 36 thuslycircumscribe an area of circular cross-section tapering in diameter fromthe edge segments 34 to the forward edges of the body protrusions. Theangle at which the body protrusions 36 extend inwardly from the edgesegments 34 may vary, but in one embodiment the body protrusions extendinwardly at an angle B of about 15° to the outer diameter of body 18 atedge segments 34 as best seen in FIG. 5.

As best shown in FIGS. 3 and 6-8, the distal tip 16 is hollow and has anopen rearward or proximal end 40 slidably and rotatably received in theopen forward end of body 18 and has a cutting window 42 located distallyof the forward end of body 18 when the outer member 12 is in alongitudinally extended position as explained further below. The cuttingwindow 42 has a plurality of directional positions facing radially,angularly or laterally outwardly or transverse to the centrallongitudinal axis 30, and the cutting window communicates with theinterior of the distal tip 16. The distal tip 16 is slidably androtatably mounted to the forward end of body 18 coaxial with the distallength portion 26 such that the central longitudinal axis of the distaltip 16 is defined by the central longitudinal axis 30 of the distallength portion. The distal tip 16 has a plurality of rotational,directional or angular positions about the central longitudinal axis 30corresponding to the directional positions for cutting window 42 asexplained further below.

The distal tip 16 includes a rearward annular shoulder 44 at rearwardend 40 and a forward annular shoulder 46 spaced forwardly from therearward shoulder 44 so as to be disposed between the rearward shoulderand the cutting window 42. The rearward and forward shoulders 44 and 46are spaced longitudinally from one another by a cylindrical segment 48of tip 16 having an outer diameter smaller than the outer diameters ofthe shoulders 44 and 46. The outer diameters of the shoulders 44 and 46are selected to be received within the lumen 38 of elongate body 18 witha close fit while still permitting relative longitudinal slidingmovement between the distal tip 16 and body 18 along the axis 30 as wellas relative rotation between the distal tip and body about axis 30. Aseal 50, such as an annular or O-ring seal of appropriate thickness, maybe disposed around the cylindrical segment 48 to prevent leakage ofirrigation fluid from the outer member as explained further below.

A plurality of arcuately or circumferentially extending tip protrusions52 extend longitudinally forwardly or distally from the forward shoulder46 to terminate at forward edges of the tip protrusions. Outer surfacesof the tip protrusions 52 define arcuate or circumferential segments ofa circle having a diameter and circumference between forward shoulder 46and the forward edges of the tip protrusions 52 such that the tipprotrusions define raised keys along the outer surface of the distal tip16 distally or forwardly of the forward shoulder 46 as best shown byFIGS. 3, 6 and 8. The tip protrusions 52 are spaced from one another atradial locations about the axis 30 by arcuately or circumferentiallyextending tip slots or keyways 53. The arcuate or circumferential widthof the tip protrusions or keys 52 is selected to be received in thewidth of the body slots or keyways 37 with a mating or complementaryfit, and the arcuate or circumferential width of the tip slots orkeyways 53 is selected to receive the width of the body protrusions orkeys 36 with a mating or complementary fit to prevent or lock the distaltip 16 and elongate body 18 against rotation relative to one anotherabout the central longitudinal axis 30 as explained further below. Tip16 comprises four tip protrusions 52 at 90° spaced radial locationsabout the axis 30 and four tip slots 53 alternatingly arranged with thetip protrusions.

The cutting window 42 depicted by way of example for distal tip 16 isnon-parallel or angled relative to the central longitudinal axis 30, andthe cutting window 42 extends from distal to proximal at an outwardangle in a direction away from the axis 30. Accordingly, the externalconfiguration of distal tip 16 in side view or longitudinal profiletapers in the distal direction from a proximal end of the cutting window42 to a distal or forward end 56 of distal tip 16. The distal tip 16comprises a cutting edge 54 along the peripheral edge of the cuttingwindow 42 formed by way of example as a plurality of cutting teeth alongthe peripheral edge of the cutting window. However, the cutting window42 can be provided without a cutting edge. The cutting teeth for cuttingedge 54 are arranged on opposite sides of the axis 30 and extend fromdistal to proximal in side view or longitudinal profile so as to benon-parallel or angled to the axis 30 in accordance with the angle ofthe cutting window 42 as best shown in FIG. 3. The cutting window 42 islocated distally of the forward edges of the tip protrusions 52, and thedistal tip 16 terminates distally at the distal or forward end 56. Thedistal tip 16 and the body 18 are preferably made of a medicallyacceptable or biocompatible material such as stainless steel. The distaltip 16 is depicted as being integrally, unitarily or monolithicallyformed as a single piece or part such that the distal tip 16 is ofone-piece construction. However, the distal tip 16 may be of multi-partconstruction for greater ease of manufacture and/or reduced cost asrepresented by the two-part distal tip shown in FIGS. 16 and 17.

The distal tip 16 is assembled to the elongate body 18 by beinginserted, distal end 56 first, in the open proximal end of the body andpushed longitudinally distally or forwardly therein to extend distallyfrom the open forward end of the body. With the body protrusions 36longitudinally aligned with the tip slots 53 and the body slots 37longitudinally aligned with the tip protrusions 52, the distal tip 16can be maximally extended from the forward end of elongate body 18 in alongitudinally extended position for the outer member 12. The distancethat the distal tip 16 extends from the forward end of the body 18 inthe longitudinally extended position is limited or controlled due toengagement or abutment of the inwardly angled inner surfaces of the bodyprotrusions 36 with the forward shoulder 46. In the longitudinallyextended position, the body protrusions and slots 36 and 37 will becooperatively interengaged with the tip slots and protrusions 53 and 52,respectively, with there being a tip protrusion 52 between each radiallyadjacent pair of body protrusions 36 to prevent relative rotationbetween the tip 16 and body 18 about the axis 30. Accordingly, thecutting window 42 will be locked in an initial one of the plurality ofradial, angular or directional positions therefor about axis 30 andrelative to bend 24 and will face in a predetermined direction relativeto axis 30 and bend 24 corresponding to this radial, angular ordirectional position. The distal tip 16 will also be locked in one of aplurality of predetermined rotational positions for the distal tip aboutits axis 30 corresponding to the directional positions for cuttingwindow 42, respectively.

The outer member 12 has a longitudinally retracted position in which thetip protrusions and slots 52 and 53 are disposed proximally of andthereby disengaged from the body slots and protrusions 37 and 36,respectively. The longitudinally retracted position is obtained viarelative longitudinal movement between the distal tip 16 and body 18whereby the tip is retracted relative to or within the body from thelongitudinally extended position. Accordingly, the rearward end 40 oftip 16 is disposed closer to the forward end of body 18 in thelongitudinally extended position than in the longitudinally retractedposition. In the longitudinally retracted position, the tip 16 and body18 are rotatable relative to each other about the axis 30, allowing thedistal tip 16 to be rotationally indexed about its axis 30 to anotherpredetermined rotational position in which the body protrusions andslots 36 and 37 are longitudinally aligned with the tip slots andprotrusions 53 and 52, respectively. The another rotational positioncorresponds to another directional position for the cutting window 42 inwhich the cutting window faces in another predetermined directionrelative to axis 30 and bend 24. In order to lock the distal tip 16 inthe another rotational position, the outer member 12 is moved from thelongitudinally retracted position to the longitudinally extendedposition to engage the body protrusions and slots 36 and 37 with the tipslots and protrusions 53 and 54, respectively, thereby preventingrelative rotation between the distal tip 16 and elongate body 18 aboutaxis 30.

The distal tip 16 is rotatable 360° about its axis 30 and is designedfor four rotationally indexed positions corresponding to the 90° spacedradial locations for the body protrusions 36 and tip slots 53. However,the distal tip could be designed for any plurality of rotationallyindexed positions about axis 30. The predetermined directional positionsfor cutting window 42 associated with the four rotational positions oftip 16 correspond to the cutting window facing upwardly, laterally,downwardly and medially, respectively, to axis 30 and the center ofcurvature R for bend 24, but could correspond to the cutting windowfacing in various other directions.

Inner member 14, which may be considered an inner blade member, is shownas being tubular but may be tubular or non-tubular. Inner member 14 hasa proximal length region 58 extending distally from an inner member hub60, a distal cutting tip 62 formed as or provided with a cutting edge 64and a flexible or bendable region 66 between proximal length region 58and cutting tip 62. The cutting tip 62 is adapted to cut anatomicaltissue, and the cutting tip depicted by way of example for inner member14 includes a cutting opening 68 communicating with a lumen 70 throughthe inner member and the cutting edge 64 extending along a peripheraledge of opening 68. The cutting edge 64 may be designed in various ways,for example as a plurality of cutting teeth along opposite sides of theperipheral edge of the cutting opening 68 as shown for inner member 14,and could also be designed as a burr. The cutting edge 64 and cuttingopening 68 are non-parallel or angled to the central longitudinal axisof the inner member 14 as described for the cutting window 42.

When the inner member 14 is disposed within the outer member 12 amaximum or full insertion distance as shown in FIGS. 1 and 9, the innermember extends through the outer member hub 20 with the inner member hub60 disposed proximally of the outer member hub, the cutting edge 64exposed by the cutting window 42 of distal tip 16, the distal outersurface of the cutting tip 62 in contact with the distal inner surfaceof distal tip 16 at a contact area 72, and the flexible region 66disposed within or adjacent the bend 24 so that the inner member followsor conforms to the longitudinally or axially bent, curved or angledconfiguration of the outer member. Of course, the inner member 14 mayinclude one or more flexible regions for being disposed in one or morebends of outer member 12. The length of the inner member 14 disposed inthe lumen of outer member 12 to its full insertion distance places theouter member 12 in the longitudinally extended position due to thecontact between the inner member and the outer member at contact area72, and the inner member and outer member hubs 60 and 20 are connectibleto a powered surgical handpiece 74 as depicted in FIGS. 1 and 9.Connection of the hubs 60, 20 to the handpiece 74 secures the innermember 14 to the outer member 12 with the inner member disposed the fullinsertion distance in the outer member and thereby locks the outermember in the longitudinally extended position with the distal tip 16locked in a selected predetermined rotational position. In FIG. 9, thedistal tip 16 is locked in a selected predetermined rotational positioncorresponding to a predetermined directional position for cutting window42 in which the cutting window faces upwardly toward the center ofcurvature for the bend 24. The proximal length region 58 is rigid andtransmits torque from the powered surgical handpiece 74 via the flexibleregion 66 to rotate the cutting tip 62 when the inner member 14 isrotated relative to and within the outer member 12 by the poweredsurgical handpiece. The flexible region 66 allows the inner member 14 toconform to the angled configuration of the outer member 12 as it isrotated relative to and within the outer member. The hubs 20 and 60 areadapted to be removably coupled with the powered surgical handpiece 74,and the powered surgical handpiece may be of the type disclosed in U.S.Pat. No. 5,916,231 to Bays, the entire disclosure of which isincorporated herein by reference. The handpiece could include a springbias for the inner member hub by which the inner member 14 isresiliently biased distally to its full insertion distance within theouter member 12.

The cutting tip 62 can have various configurations depending on thesurgical procedure to be performed and the type of cutting action. Thecutting tip 62 accesses anatomical tissue at an operative site via thecutting window 42 of distal tip 16 and is aligned with or disposedadjacent the window 42 as the inner member 14 is rotated within theouter member 12. The distal tip 16 of the outer member 12 can beprovided with or without a cutting edge and is shown as having cuttingedge 54 cooperable with the cutting edge 64 of inner member 14 to cutanatomical tissue as the inner member is rotated within the outermember. The cutting edge 54 may be designed in various ways, for exampleas a sharp peripheral edge of window 42 or as a plurality of cuttingteeth along the peripheral edge of window 42 as shown for outer member12. The cutting edge 64 moves past the cutting edge 54 as the innermember is rotated within the outer member to cut anatomical tissue. Whenthe cutting edge 64 coincides with the cutting window 42 as shown inFIG. 9, the angles of the cutting edge 64 and cutting window 42coincide, such that the external longitudinal configuration or profileof the instrument corresponds essentially to the external longitudinalconfiguration or profile of the distal tip 16. Anatomical debris may beaspirated from the operative site through the lumen 70 of inner member14, the opening 68 of the inner member forming a suction inlet throughwhich debris is aspirated. Where the powered surgical handpiece of theaforementioned Bays patent is used, the debris is aspirated through theinner member and the handpiece. The flexible region 66 of the innermember 14 can be formed in various ways as represented by the RADenoid®blades of Medtronic Xomed Surgical Products and by U.S. Pat. No.5,922,003 to Anctil et al, the entire disclosure of which isincorporated herein by reference. The inner member is preferably made ofa medically acceptable or biocompatible material such as stainlesssteel.

Aspiration may be accomplished in the angled tissue cutting instrumentthrough the inner member, through the outer member, such as between theouter member and the inner member, or in any other suitable manner.However, it should be appreciated that the angled tissue cuttinginstrument can be provided and/or used without aspiration. The angledtissue cutting instrument may be provided with or without an irrigationpassage or channel for supplying irrigation or flushing fluid to thecutting site, and both aspiration and irrigation may be provided in theangled tissue cutting instrument. Irrigation may be provided along theinstrument in various ways including internally through the innermember, internally through the outer member, such as between the outermember and the inner member, externally along the outer member, or inany other suitable manner. The angled tissue cutting instrument mayinclude an external irrigation channel as disclosed in U.S. Pat. No.5,782,795 to Bays and U.S. Pat. No. 6,312,438 B1 to Adams, the entiredisclosures of which are incorporated herein by reference. The Adamspatent is also representative of a burr tip which may be used as thecutting tip in the angled tissue cutting instrument and of an aspirationpassage and aspiration port which may be incorporated in the innermember. The outer member hub 20 is illustrated with an optional nipple76 providing an irrigation port in communication with the inlet port 32of outer member 12 by which irrigation fluid may be supplied to theouter member lumen 38 for flow between the inner and outer members anddischarge at the operative site via the cutting window 42. Leakage ofirrigation fluid between the tip 16 and body 18 is prevented by seal 50.

FIGS. 1, 2 and 9 illustrate the distal tip 16 in a first or initialpredetermined rotational position and the cutting window 42 in a firstor initial predetermined directional position in which the cuttingwindow faces upwardly, i.e., toward the center of curvature R for thebend 24, which extends in a particular direction relative to or from thehandpiece 74. To rotationally index the distal tip 16 and thereby varythe directional position of the cutting window 42 relative to the bend24, the inner member 14 is withdrawn or moved proximally relative to theelongate body 18 of outer member 12 from its full insertion distance anamount sufficient to permit movement of the outer member from thelongitudinally extended position to the longitudinally retractedposition as shown in FIG. 10. Typically, the outer member 12 will beplaced in the longitudinally retracted position by depressing the tip 16longitudinally proximally relative to and toward the body 18 with amanually applied proximal axial force, such as that applied by a finger,or a mechanically applied force, such as that as applied by the indexingtool described below, while the body 18 is grasped. Withdrawing theinner member 14 proximally within the outer member 12 without removingthe inner member entirely from the outer member allows the inner memberto serve as a stop or abutment limiting the distance that the tip 16 maybe retracted in the body 18 in the longitudinally retracted position sothat a sufficient portion of the tip continues to extend from theforward end of the body to enable the tip to be manually or mechanicallygrasped. As shown in FIG. 10, the distal tip 16 contacts the cutting tip62 at contact area 72 in the longitudinally retracted position so thatthe distal tip 16 is prevented from being retracted too far proximallywithin the body 18 and is prevented from being retracted entirely withinthe body. Depending on how the hubs 20 and 60 are mounted to thehandpiece, it may be necessary to detach the hubs from the handpiece inorder to withdraw the inner member 14 proximally relative to theelongate body 18. Withdrawal of the inner member 14 proximally relativeto the elongate body 18 may be performed prior to moving the outermember 12 from its longitudinally extended position to itslongitudinally retracted position or simultaneously with moving theouter member from its longitudinally extended position to itslongitudinally retracted position. For example, the inner member 14 maybe moved proximally relative to and within the elongate body 18 from itsfull insertion distance as a result of moving the distal tip 16proximally relative to the elongate body 18 to obtain the longitudinallyretracted position for the outer member 12. Where the handpiece springbiases the inner member 14 distally within the outer member 12, theinner member may be moved proximally from its full insertion distancewhile the inner and outer members remain attached to the handpiece and,therefore, the outer member may be moved from the longitudinallyextended position to the longitudinally retracted position while theinner and outer members are attached to the handpiece.

When the outer member 12 is in the longitudinally retracted position,the body and tip protrusions 36, 52 are disengaged from the tip and bodyslots 53, 37, respectively, allowing rotational indexing of the distaltip 16 from the initial rotational position to a subsequent or anotherrotational position. In accordance with one manner of rotationalindexing, the distal tip 16 is rotationally indexed by grasping thedistal tip manually with the fingers or mechanically with a tool whilethe elongate body 18 is rotated relative to the tip about the axis 30,the inner member 14 conforming to the outer member 12 as the body 18 isrotated as shown in FIG. 10. Use of a tool to grasp the distal tip 16 ispreferred in order to avoid hand contact with the sharp cutting edge oredges on or exposed from the distal tip and to avoid tearing of asurgical glove worn on the hand when contacting the distal tip. Inanother manner of rotational indexing described below, the distal tip 16is rotated relative to the elongate body 18 while the elongate body isgrasped.

FIG. 10 shows the distal tip 16 indexed to a subsequent rotationalposition 180° from the initial rotational position and in which thecutting window 42 is in a subsequent or another directional position180° from the initial directional position with the window 42 facing ina direction away from the center of curvature R for the bend 24. Oncethe distal tip 16 has been rotationally indexed to the selectedrotational position, the outer member 12 is moved from thelongitudinally retracted position back to the longitudinally extendedposition as illustrated in FIG. 11 and as permitted due to longitudinalalignment of the protrusions 36, 52 with the slots 53, 37, respectively.Movement of the outer member 12 to the longitudinally extended positionmay be accomplished by advancing the inner member 14 distally within theouter member 12 to the full insertion distance whereby the tip 16 ismaximally extended from the body 18 causing the body protrusions andslots 36 and 37 to cooperatively interengage with the tip slots andprotrusions 53 and 52, respectively, to lock the distal tip in thesubsequent rotational position. As the outer member 12 is moved from thelongitudinally retracted position to the longitudinally extendedposition, there may be some relative rotation between the distal tip 16and elongate body 18 as the tip and body engagement structure self-alignto correct for misalignments when the distal tip is not indexed exactlyto an established rotational position. Accordingly, rotational indexingof the distal tip 16 to a selected rotational position does not requirethat the distal tip 16 be rotated exactly to an established rotationalposition. Where the outer and inner members 12 and 14 have been detachedfrom the handpiece, the outer and inner member hubs 20 and 60 arereattached to the handpiece 74 once the inner member 14 is advanced inthe outer member 12 to the full insertion distance, thereby locking theouter member in the longitudinally extended position so that the distaltip 16 is locked in the subsequent rotational position as shown in FIG.11. Where the outer and inner members 12 and 14 have not been detachedfrom the handpiece, the spring bias provided by the handpiece on theinner member can be used to effect advancement of the inner member toits full insertion distance automatically when the proximal force on thedistal tip 16 is removed. FIG. 11 shows the bend 24 again extending inthe particular direction shown in FIG. 9 but with the cutting window 42now facing downwardly, i.e., away from the center of curvature R forbend 24. Accordingly, the direction of the bend 24 in relation to thehandpiece 74 may remain the same regardless of the rotational positionselected for tip 16, and the orientation of the handpiece may remain thesame for optimal grasping and manipulation by the surgeon.

FIG. 12 illustrates the instrument 10 with the bend 24 extending in aparticular direction to access an internal operative site and the distaltip 16 in a first rotational position with the cutting window 42 facingin the direction of the center of curvature for the bend in a firstdirectional position for the cutting window. In this position, thecutting window 42 is optimally oriented to cut anatomical tissue Tlocated superiorly or upwardly to the distal tip 16 while the bend 24extends in the particular direction. FIG. 13 depicts the bend 24extending in the particular direction with the tip 16 rotationallyindexed to a second rotational position 90° clockwise from the firstrotational position. The cutting window 42 is in a second directionalposition 90° clockwise from the first directional position and isoptimally situated to cut anatomical tissue T located laterally/mediallyto the distal tip 16. FIG. 14 depicts the bend 24 extending in theparticular direction but with the tip 16 rotationally indexed to a thirdrotational position 180° clockwise from the first rotational positionand 90° clockwise from the second rotational position. The cuttingwindow 42 is in a third directional position 180° clockwise from thefirst directional position and 90° clockwise from the second directionalposition and is optimally directed to cut anatomical tissue T locatedinferiorly or downwardly to the tip 16. The bend 24 is shown in FIG. 15extending in the particular direction but with the tip 16 rotationallyindexed to a fourth rotational position 270° clockwise from the firstrotational position, 180° clockwise from the second rotational position,90° clockwise from the third rotational position, and 90°counterclockwise from the first rotational position. The cutting window42 is in a fourth directional position 270° clockwise from the firstdirectional position, 180° clockwise from the second directionalposition, 90° clockwise from the third directional position, and 90°counterclockwise from the first directional position. In the fourthdirectional position, the cutting window 42 is optimally situated to cutanatomical tissue T medially/laterally to the tip 16. Although fourrotational positions are shown for the distal tip 16 corresponding tofour directional positions for cutting window 42 equally spaced 90° fromone another about the central longitudinal axis 30, it should beappreciated that any suitable number of rotational and directionalpositions greater than one can be provided for the distal tip 16 andcutting window 42 at equally spaced or non-equally spaced radial,rotational or angular locations about the central longitudinal axis 30of the distal tip 16. Depending on the manner in which the distal tip 16is rotatably mounted to the forward end of body 18, the distal tip 16and the body 18 may be rotated clockwise and/or counterclockwise toobtain the different rotational and directional positions.

In the illustrated embodiment, the distal tip 16 is locked in eachrotational position with all of the protrusions 36, 52 engagedsimultaneously in slots 53, 37, respectively. It should be appreciated,however, that the number of protrusions may be different than the numberof slots so that not all of the slots and protrusions need to beinterengaged when the distal tip 16 is locked in each rotationalposition. Although a plurality of protrusions is preferred, only oneprotrusion on the tip 16 or the body 18 may be necessary for engaging aselected one of a plurality of slots in the other of the tip 16 or thebody 18, and any suitable number of slots may be provided for a singleprotrusion. Similarly, only one slot may be necessary on the tip 16 orthe body 18 for engagement with a selected one of a plurality ofprotrusions on the other of the tip 16 or the body 18, and any suitablenumber of protrusions may be provided for a single slot. While the bodyprotrusions 36 are located about the central longitudinal axis 30 atradial locations corresponding to the first, second, third and fourthrotational positions described for distal tip 16, the body slots 37 canalternatively be disposed at these locations. The protrusions and slotscan be disposed at various locations, so long as each incrementalrotational engagement of the distal tip 16 and the body 18 correspondsto a desired predetermined rotational, angular, radial or directionalposition for the cutting window 42. It should also be appreciated thatany arrangement of the protrusions and slots can be reversed bysubstituting slots for the protrusions and substituting protrusions forthe slots.

The angled tissue cutting instrument 10 can be used to access aninternal operative site with the bend 24 extending in a particulardirection and to cut anatomical tissue at the operative site located indifferent directions relative to the distal tip 16 and bend 24 dependingon the rotational, radial, angular or directional position selected forthe cutting window 42. Accordingly, the angled tissue cutting instrument10 can be used for cutting in various directions relative to the bendwithout altering the bend or requiring that the orientation of theinstrument be changed. With the angled tissue cutting instrument of thepresent invention, the rotational, radial, angular or directionalposition of the cutting window in the outer member about the centrallongitudinal axis of the distal tip can be selectively adjusted relativeto the bend to position the window to face in various directionsrelative to the bend. The rotational positions for the distal tip can beequally spaced or non-equally spaced about the central longitudinal axisof the distal tip. The directional positions for the cutting window canbe equally spaced or non-equally spaced about the central longitudinalaxis of the distal tip. Cutting can be effected by the angled tissuecutting instrument via rotation, oscillation, or other movement of theinner member within the outer member.

An alternative distal tip for use in the instrument 10 is illustrated at116 in FIGS. 16 and 17. Distal tip 116 is similar to distal tip 16 butis of multi-part construction, the distal tip 116 being of two-partconstruction comprising a back part 117 and a front part 119. Back part117, which is formed separately from the front part 119 as shown in FIG.17, has a rearward annular shoulder 144 at rearward and 140 and forwardannular shoulder 146 spaced longitudinally from rearward shoulder 144 bycylindrical segment 148. As described for tip 16, a seal may be disposedaround cylindrical segment 148. The back part 117 includes a pluralityof tip protrusions 152 extending longitudinally forwardly from theforward shoulder 146 and tip slots (not visible in FIGS. 16 and 17)between the tip protrusions 152. The tip protrusions 152 are spaced fromone another at radial locations about the central longitudinal axis ofthe distal tip 116 and the distal length portion of the elongate body asdescribed for the tip protrusions 52; however, the radial locations fortip protrusions 152 about the central longitudinal axis are differentfrom the radial locations illustrated for tip protrusions 52. Four tipprotrusions 152 may be provided in back part 117 at 90 degree spacedlocations about the central longitudinal axis of the distal lengthportion of the body.

The front part 119 has the cutting window therein, which is not visiblein the sectional views of FIGS. 16 and 17. The front part 119 has anopen rearward end 121 received within an open forward end of the backpart 117 with the rearward end 121 in abutment with an internal annularshoulder 123 of back part 117 as shown in FIG. 16. The back part 117 hasa uniform inner diameter, and the front part 119 has a uniform innerdiameter from internal shoulder 123 up to the curvature of forward end156 that is the same or essentially the same as the inner diameter ofthe back part. The back part 117 can be fixedly secured in assembledrelation with the front part 119 in any suitable manner. With the backpart 117 and the front part 119 in assembled relation as shown by FIG.16, the cutting window is disposed forwardly of the tip protrusions 152and forwardly of the tip slots disposed between the tip protrusions 152.The tip protrusions 152 define raised keys along the outer surface offront part 119 distally or forwardly of the forward shoulder 146. Asshown in FIG. 16, the tip protrusions 152 extend along the outer surfaceof front part 119 in contact therewith. As described for tip 16, thearcuate or circumferential width of the tip protrusions or keys 152 isselected to be received in the width of the body slots or keyways with amating or complementary fit, and the arcuate or circumferential width ofthe tip slots or keyways is selected to receive the width of the bodyprotrusions or keys with a mating or complementary fit to lock thedistal tip 116 and the body against rotation relative to one another.The distal tip 116 may be preferred for ease of manufacturing and/orreduced cost, and the distal tip can be formed of two or more separateparts assembled together.

An indexing tool 11 for use with the angled tissue cutting instrument 10is illustrated in FIGS. 18-21. The indexing tool 11 is provided formoving the outer member 12 from the longitudinally extended position tothe longitudinally retracted position and for rotationally indexing theretracted distal tip 16 relative to the elongate body 18 without theuser's hand or fingers contacting the distal tip 16 and especially thecutting edge or edges on and/or exposed from the distal tip 16. Theindexing tool 11 comprises a retention element 13 having a socket 15 forreceiving a forward portion of distal tip 16 and a handle 25 extendingfrom the retention element 13. The retention element 13 is cylindricalin external configuration from a first end of the retention element to asecond end of the retention element connected to handle 25. However, theretention element 13 could have any suitable external configurationother than cylindrical. An entry opening 27 in the first end of theretention element 13 establishes communication with the socket 15 fromexternally of the indexing tool 11 for the insertion of distal tip 16into the socket 15 through the entry opening 27. The entry opening 27 iscoaxial with a central longitudinal axis of the retention element 13,and the socket 15 extends longitudinally in the retention element fromthe entry opening 27 to an internal end surface of the retentionelement. As best shown in FIG. 21, the socket 15 has a configuration tomate with the external longitudinal configuration or profile of theforward portion of distal tip 16 when the distal tip 16 is in apredetermined insertion orientation relative to the socket 15. In thecase of distal tip 16, the longitudinal profile or configuration of thesocket 15 tapers from the entry opening 27 toward the internal endsurface of the retention member in accordance with the distal taper ofthe forward portion of distal tip 16. The retention element 13 thuslyincludes an angled internal surface 29 defining one side of socket 15and extending longitudinally from entry opening 27 at an anglecorresponding to the angle of cutting window 42. The angled internalsurface 29 is disposed radial to the central longitudinal axis of theretention element 13, and the indexing tool 11 includes indicia 31 on anexternal surface of the retention element at the same radial location tothe central longitudinal axis of the retention element as the angledinternal surface 29. Accordingly, the indicia 31 is radially alignedwith the angled internal surface 29.

The socket 15 removably receives the forward portion of distal tip 16with a mating or complementary fit when the distal tip is inserted inthe socket through entry opening 27 with the distal tip in thepredetermined insertion orientation relative to the socket. When thedistal tip 16 is not in the predetermined insertion orientation relativeto the socket 15, the distal tip cannot properly be inserted into thesocket with a mating fit. The distal tip 16 is inserted through entryopening 27 and placed deeper in the socket 15 with its centrallongitudinal axis 30 coaxially aligned with the central longitudinalaxis of the retention element 13. The predetermined insertionorientation for the distal tip 16 in socket 15 corresponds to anorientation for the distal tip relative to the socket in which thecutting window 42 is aligned with the indicia 31 and is thusly at thesame radial location to the aligned central longitudinal axes as theangled internal surface 29. Accordingly, regardless of the directionalorientation of the cutting window 42 relative to the bend 24, the distaltip 16 can properly be inserted in the socket 15 with a mating fit onlywhen the cutting window is in a particular predetermined orientationrelative to the socket. The angled internal surface 29 assists inguiding the distal tip 16 into the socket 15 as the cutting window 42 ismoved along the angled internal surface.

The indicia 31 is depicted as an arrow pointing toward the entry opening27 and extending longitudinally along the retention element 13 parallelto the central longitudinal axis of the retention element. However, theindicia 31 could comprise any suitable symbolic and/or verbalidentifiers. The indicia 31 points to the location of the entry opening27 to facilitate insertion of the distal tip 16 in socket 15, identifiesthe radial location for the cutting window 42 to obtain thepredetermined orientation needed for proper insertion of the distal tipin the socket, and depicts the longitudinal direction of movement forplacement of the retention element over the distal tip 16 to positionthe distal tip in the socket. The indicia 31 is thusly multi-functional.The indicia 31 may be raised or elevated from the surrounding externalsurface of the retention element 13 to serve as both a visual andtactile indicator.

The handle 25 may have any suitable configuration to facilitate graspingby the hand of a user. The external surfaces of the handle may haveraised lands configured as product labels and/or to facilitate grasping.The handle 25 has opposed grasping surfaces 33 a and 33 b presenting anovoid peripheral configuration with a truncated end opposite theretention element 13 as shown in FIG. 18. The grasping surfaces 33 a, 33b may have a gently curving convex curvature as illustrated in FIGS. 19and 21 to facilitate grasping between the thumb and forefinger with theindicia 31 facing upwardly. The indexing tool 11 can be formedintegrally, unitarily or monolithically as a single component and may bea machined or molded component. The indexing tool 11 may be made ofmedically acceptable plastic or any other suitable material and may bedisposable for single patient use. The indexing tool 11 may be madeavailable with sockets of various different sizes and/or variousdifferent configurations for various angled tissue cutting instrumentsof different distal tip sizes and/or configurations. It should beappreciated that the indexing tool 11 can be provided with a socket thatis designed to accept different sizes and/or different configurations ofdistal tips.

FIG. 22 depicts an angled tissue cutting instrument kit 35 comprisingangled tissue cutting instrument 10 and indexing tool 11. The angledtissue cutting instrument 10 and indexing tool 11 may be suppliedtogether in a package as kit 35 in a sterile condition ready for use ina surgical procedure. The indexing tool 11 may be used to move the outermember 12 from the longitudinally extended position to thelongitudinally retracted position and to rotationally index the distaltip 16 of the outer member 12 when the outer member is in thelongitudinally retracted position. To move the outer member 12 from thelongitudinally extended position to the longitudinally retractedposition mechanically using indexing tool 11, the elongate body 18 ofouter member 12 is typically grasped in one hand and the handle 25 ofindexing tool 11 is typically grasped in the opposite hand. The indexingtool 11 and/or the elongate body 18 is/are manipulated to place thedistal tip 16, forward end 56 first, through the entry opening 27 andinto the socket 15 with the distal tip in the predetermined insertionorientation relative to the socket. The distal tip 16 is placed in thesocket 15 with its central longitudinal axis 30 coaxial with the centrallongitudinal axis of the retention element 13, with the distal tip beingcoaxially aligned with the retention element due to the entry opening 27and internal surface 29 centering the distal tip 16 in the socket 15.The distal tip 16 is inserted in the socket 15 with the cutting window42 aligned with the indicia 31 so as to be disposed at the same radiallocation to the aligned central longitudinal axes as the angled internalsurface 29. The distal tip 16 is placed deeper into the socket 15 bymoving the indexing tool 11 longitudinally toward the outer member 12and/or by moving the outer member longitudinally along the centrallongitudinal axis 30 toward the indexing tool 11. The angled internalsurface 29 of the socket 15 guides the distal tip 16 as it is placed inthe socket and insures proper positioning of the distal tip in thesocket. Placing the distal tip 16 deeper into the socket 15 causes thedistal tip to engage the socket with a mating fit by which the retentionelement 13 may exert a proximal axial force against the distal tip 16along the central longitudinal axis 30. Establishment of the mating fitis facilitated by alignment of the cutting edge and cutting opening 68with the cutting window 42. The proximal force applied to the distal tip16 by the indexing tool 11 along the central longitudinal axis 30 causesretraction of the distal tip 16 relative to the elongate body 18 to movethe outer member 12 from the longitudinally extended position to thelongitudinally retracted position, thereby disengaging the tipengagement structure from the body engagement structure to allowrotational indexing of the distal tip 16. Retraction of the distal tip16 relative to the elongate body 18 may be preceded by the inner member14 being moved proximally relative to the elongate body 18 from its fullinsertion distance, or the inner member 14 may be moved proximally fromits full insertion distance by the distal tip 16 being retractedrelative to the elongate body 18 as discussed above for manual or handoperation.

In order to rotationally index the distal tip 16 mechanically using theindexing tool 11 when the outer member 12 is in the longitudinallyretracted position, the handle 25 is rotated to correspondingly rotatethe retention element 13 about its central longitudinal axis which iscoaxially aligned with the central longitudinal axis 30 of the distaltip 16 received in the socket 15. The retention element 13 appliesrotational force to the distal tip 16 due to the mating fit of thedistal tip in the socket 15, and the distal tip is thereby rotated aboutits central longitudinal axis 30 correspondingly with the retentionelement. As shown by an arrow in FIG. 22, the indexing tool 11 may berotated clockwise or counterclockwise to rotationally index the distaltip 16 clockwise or counterclockwise to a desired rotational positioncorresponding to a desired directional position for the cutting window42. Since the indicia 31 is located at the same radial position as thecutting window 42, the indicia serves as a marker indicating the radialposition of the cutting window about the central longitudinal axis 30 asthe distal tip 16 is rotationally indexed. Once the cutting window 42has been rotated to the selected directional position, the outer member12 is moved from the longitudinally retracted position back to thelongitudinally extended position to lock the cutting window in theselected directional position and the indexing tool 11 is removed fromthe distal tip 16. The outer member 12 is moved from the longitudinallyretracted position to the longitudinally extended position by advancingthe inner member 14 distally within the outer member 12 to the fullinsertion distance. As discussed above, the inner member 14 may beadvanced distally within the outer member 12 to the full insertiondistance by manually inserting and advancing the inner member within theouter member or by mechanical spring pressure provided on the innermember by the handpiece. The indexing tool 11 can be removed from thedistal tip 16 prior to or subsequent to moving the outer member 12 fromthe longitudinally retracted position to the longitudinally extendedposition. Use of the indexing tool 11 avoids contact of the user's handor fingers with the distal tip 16 thereby avoiding the risk of tearing asurgical glove worn on the user's hand during a surgical procedure inwhich indexing of the distal tip is performed.

Inasmuch as the present invention is subject to various modifications,additions or changes in detail, the preferred embodiments describedherein should be considered illustrative only and should not be taken ina limiting sense since various modifications can be made thereto withoutdeparting from the scope of the invention as defined by the appendedclaims.

1. An angled tissue cutting instrument comprising an elongate outer member comprising an elongate body having a bend and a forward end and a distal tip rotatably mounted to said forward end, said distal tip including a central longitudinal axis and a cutting window having a directional position radial to said central longitudinal axis, said distal tip and said body being selectively rotatable relative to one another about said central longitudinal axis to move said cutting window to a different directional position radial to said central longitudinal axis; and an elongate inner member movably disposed within said outer member and including a flexible region adjacent said bend and a cutting edge exposed from said cutting window for cutting anatomical tissue when said inner member is moved relative to and within said outer member.
 2. The angled tissue cutting instrument recited in claim 1 wherein said inner member is rotatably disposed within said outer member.
 3. The angled tissue cutting instrument recited in claim 1 wherein said inner member is removably disposed within said outer member.
 4. The angled tissue cutting instrument recited in claim 1 wherein said cutting window is movable to a plurality of directional positions located at 90° spaced locations about said central longitudinal axis.
 5. The angled tissue cutting instrument recited in claim 1 and further comprising means for releasably locking said cutting window in each of said directional positions.
 6. The angled tissue cutting instrument recited in claim 5 wherein said distal tip includes tip engagement structure and said body includes body engagement structure selectively cooperatively interengageable with said tip engagement structure to lock said cutting window in each of said directional positions.
 7. The angled tissue cutting instrument recited in claim 6 wherein said tip engagement structure includes at least one tip protrusion radial to said central longitudinal axis and said body engagement structure includes a plurality of body slots at radial locations about said central longitudinal axis, said at least one tip protrusion being selectively cooperatively interengageable with said body slots, respectively, to prevent relative rotation between said distal tip and said body about said central longitudinal axis when said cutting window is in each of said directional positions.
 8. The angled tissue cutting instrument recited in claim 7 wherein said tip engagement structure includes a plurality of tip protrusions at radial locations about said central longitudinal axis and a plurality of tip slots each located between a pair of radially adjacent ones of said tip protrusions, and said body engagement structure further includes a plurality of body protrusions each located between a pair of radially adjacent ones of said body slots, said tip protrusions and said tip slots being selectively cooperatively interengageable with said body slots and said body protrusions, respectively, to prevent relative rotation between said distal tip and said body about said central longitudinal axis when said cutting window is in each of said directional positions.
 9. The angled tissue cutting instrument recited in claim 6 wherein said tip engagement structure includes at least one tip slot radial to said central longitudinal axis and said body engagement structure includes a plurality of body protrusions at radial locations about said central longitudinal axis, said at least one tip slot being selectively cooperatively interengageable with said body protrusions, respectively, to prevent relative rotation between said distal tip and said body about said central longitudinal axis when said cutting window is in each of said directional positions.
 10. The angled tissue cutting instrument recited in claim 1 wherein said bend comprises a rigid bend formed in said body.
 11. The angled tissue cutting instrument recited in claim 6 wherein said distal tip comprises a back part and a front part assembled to said back part, said back part comprising said tip engagement structure and said front part comprising said cutting window.
 12. The angled tissue cutting instrument recited in claim 6 wherein said distal tip is formed integrally unitarily as one piece.
 13. An angled tissue cutting instrument comprising an elongate outer member including an elongate body having a bend and a forward end and a distal tip mounted at said forward end, said distal tip including a central longitudinal axis and a cutting window facing in a direction transverse to said central longitudinal axis, said distal tip and said body being selectively rotatable relative to one another about said central longitudinal axis to rotationally index said distal tip to a plurality of rotational positions about said central longitudinal axis, said distal tip and said body being selectively movable longitudinally relative to one another between a longitudinally extended position for said outer member and a longitudinally retracted position for said outer member, said distal tip being releasably locked in a selected one of said rotational positions when said outer member is in said longitudinally extended position, and being unlocked from said selected rotational position when said outer member is in said longitudinally retracted position; and an elongate inner member movably disposed within said outer member and including a flexible region adjacent said bend and a cutting edge exposed from said cutting window for cutting anatomical tissue when said inner member is moved relative to and within said outer member.
 14. The angled tissue cutting instrument recited in claim 13 wherein said body includes a proximal length portion extending distally to said bend and a distal length portion extending from said bend to said forward end, said distal length portion being coaxial with said distal tip.
 15. The angled tissue cutting instrument recited in claim 13 wherein said rotational positions are equally spaced about said central longitudinal axis.
 16. The angled tissue cutting instrument recited in claim 15 wherein said cutting window has a plurality of directional positions about said central longitudinal axis corresponding to said rotational positions, respectively.
 17. The angled tissue cutting instrument recited in claim 13 wherein said bend is rigid and said inner member is rotatably disposed within said outer member.
 18. The angled tissue cutting instrument recited in claim 13 and further comprising tip engagement structure on said distal tip and body engagement structure on said body, said body engagement structure being cooperatively interengaged with said tip engagement structure when said outer member is in said longitudinally extended position to prevent relative rotation between said distal tip and said body about said central longitudinal axis and being disengaged from said tip engagement structure when said outer member is in said longitudinally retracted position to permit relative rotation between said distal tip and said body about said central longitudinal axis.
 19. The angled tissue cutting instrument recited in claim 18 wherein said tip engagement structure and said body engagement structure are located at 90° spaced radial locations about said central longitudinal axis.
 20. The angled tissue cutting instrument recited in claim 18 wherein said distal tip includes a rearward end slidably disposed in a forward end of said body.
 21. The angled tissue cutting instrument recited in claim 20 wherein said distal tip is formed monolithically as a single part.
 22. The angled tissue cutting instrument recited in claim 20 wherein said tip engagement structure is formed on a back part of said distal tip and said cutting window is formed in a front part of said distal tip, said front part having a rearward end fixedly secured in a forward end of said back part, said back part having a rearward end defining said rearward end of said distal tip.
 23. An angled tissue cutting instrument comprising an elongate outer member including an elongate body having a proximal end, a forward end and a bend between said proximal end and said forward end, and a distal tip mounted to said forward end, said distal tip having a central longitudinal axis and a cutting window facing transverse to said central longitudinal axis, said distal tip and said body being selectively rotatable relative to one another about said central longitudinal axis to locate said distal tip at a plurality of rotational positions about said central longitudinal axis; an elongate inner member rotatably disposed within said outer member and having a maximum insertion distance within said outer member wherein a cutting edge of the inner member is exposed from said cutting window for cutting anatomical tissue when said inner member is rotated relative to and within said outer member, said inner member being movable proximally from said maximum insertion distance, said distal tip being locked in one of said rotational positions when said inner member is disposed said maximum insertion distance within said outer member and being unlocked from said one of said rotational positions when said inner member is moved proximally from said maximum insertion distance.
 24. The angled tissue cutting instrument recited in claim 23 wherein said distal tip and said body are movable longitudinally relative to one another between a longitudinally extended position for said outer member and a longitudinally retracted position for said outer member, said distal tip and said body being prevented from rotating relative to one another about said central longitudinal axis in said longitudinally extended position and being permitted to rotate relative to one another about said central longitudinal axis in said longitudinally retracted position, said outer member being maintained in said longitudinally extended position in response to said inner member being disposed said maximum insertion distance within said outer member and being movable to said longitudinally retracted position in response to said inner member being moved proximally from said maximum insertion distance.
 25. The angled tissue cutting instrument recited in claim 24 wherein said distal tip is maximally extended distally from said body in said longitudinally extended position and is retracted proximally relative to said body in said longitudinally retracted position.
 26. The angled tissue cutting instrument recited in claim 24 wherein said distal tip includes tip engagement structure and said body includes body engagement structure engaged with said tip engagement structure to prevent relative rotation between said distal tip and said body about said central longitudinal axis in said longitudinally extended position and disengaged from said tip engagement structure to permit relative rotation between said distal tip and said body about said central longitudinal axis in said longitudinally retracted position.
 27. The angled tissue cutting instrument recited in claim 23 wherein said distal tip includes tip engagement structure and said body includes body engagement structure engaged with said tip engagement structure when said inner member is disposed in said outer member said maximum insertion distance to prevent relative rotation between said distal tip and said body about said central longitudinal axis and disengaged from said tip engagement structure when said inner member is moved proximally from said maximum insertion distance to permit relative rotation between said distal tip and said body about said central longitudinal axis.
 28. The angled tissue cutting instrument recited in claim 23 wherein said inner member includes a proximal end and further including a handpiece connectible to said proximal end of said outer member and said proximal end of said inner member to secure said inner member within said outer member said maximum insertion distance.
 29. An indexing tool for an angled tissue cutting instrument having an inner member disposed in an outer member including an elongate body and a distal tip having a cutting window, comprising a retention element having a central longitudinal axis and a socket for removably receiving the distal tip of the outer member of the angled tissue cutting instrument, said socket having a configuration to mate with an external configuration of the distal tip when the distal tip is in an insertion orientation relative to said socket; external indicia alignable with the cutting window of the distal tip to obtain the insertion orientation for the distal tip relative to said socket; and a handle extending from said retention element, said handle being movable to move said retention element longitudinally along said central longitudinal axis to apply axial force to the distal tip received in said socket by which the distal tip is retracted proximally relative to the elongate body and to move said retention element rotationally about said central longitudinal axis to apply rotational force to the retracted distal tip received in said socket by which the distal tip is rotated relative to the elongate body.
 30. The indexing tool recited in claim 29 wherein said indicia is located on said retention element radial to said central longitudinal axis.
 31. The indexing tool recited in claim 30 wherein said indicia comprises an arrow extending parallel to said central longitudinal axis.
 32. The indexing tool recited in claim 29 wherein said configuration of said socket mates with the external configuration of the distal tip with said central longitudinal axis of said retention element coaxially aligned with a central longitudinal axis of the distal tip.
 33. The indexing tool recited in claim 31 wherein said arrow is raised from an external surface of said retention element.
 34. An angled tissue cutting instrument kit comprising an angled tissue cutting instrument including an elongate outer member and an elongate inner member movably disposed in said outer member, said outer member comprising an elongate body having a bend and a forward end and a distal tip mounted on said forward end, said distal tip having a central longitudinal axis and a cutting window radial to said central longitudinal axis, said distal tip being movable longitudinally relative to said elongate body from a longitudinally extended position to a longitudinally retracted position in response to axial force on said distal tip, said distal tip being rotatable relative to said elongate body about said central longitudinal axis in said longitudinally retracted position to adjust the radial position of said cutting window about said central longitudinal axis in response to rotational force on said distal tip, said distal tip being prevented from rotating relative to said elongate body about said central longitudinal axis in said longitudinally extended position to lock said cutting window in a selected radial position about said central longitudinal axis; and an indexing tool comprising a retention element having a socket for removably receiving said distal tip and a handle extending from said retention element, said indexing tool being movable via said handle to apply said axial force and said rotational forces on said distal tip.
 35. The angled tissue cutting instrument kit recited in claim 34 wherein said distal tip has an external configuration and said socket has a configuration to mate with said external configuration of said distal tip.
 36. The angled tissue cutting instrument kit recited in claim 35 wherein said distal tip mates with said socket when said distal tip is in an insertion orientation relative to said socket and does not mate with said socket when said distal tip is not in said insertion orientation.
 37. The angled tissue cutting instrument kit recited in claim 36 wherein said indexing tool further comprises external indicia and said insertion orientation corresponds to alignment of said cutting window with said indicia.
 38. The angled tissue cutting instrument kit recited in claim 37 wherein said retention element has a central longitudinal axis, said distal tip mates with said socket with said longitudinal axis of said distal tip coaxial with said central longitudinal axis of said retention element, and said indicia is disposed on said retention element radial to said central longitudinal axis of said retention element.
 39. The angled tissue cutting instrument kit recited in claim 38 wherein said retention element comprises an arrow parallel to said central longitudinal axis of said retention element.
 40. The angled tissue cutting instrument kit recited in claim 34 wherein said retention element and said handle are formed monolithically as a single component.
 41. The angled tissue cutting instrument kit recited in claim 34 wherein said cutting window is angled relative to said central longitudinal axis of said distal tip and said socket is partly defined by an angled internal surface of said retention element having an angle corresponding to the angle of said cutting window.
 42. The angled tissue cutting instrument kit recited in claim 41 wherein said retention element includes a central longitudinal axis, said angled internal surface is radial to said central longitudinal axis of said retention element and said retention element further comprises external indicia radially aligned with said angled internal surface. 